Starter for internal-combustion engines



Aug. 17, 1948. D. L. MILLER STARTER FOR INTERNAL-COMBUSTION ENGINES Filed llay 3, 1945 lllI-Illlllla lull-ll ll |||ll Wan L fi/ILLL'Z M A M1 Patented Aug. 17, 1948 STARTER FOR INTERNAL-COMBUSTION ENGINES Donald L. Miller, Pine City, N. Y., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application May 3, 1945, Serial No. 591,655

Claims. 1

The present invention relates to a starter for internal combustion engines and more particularly to that type in which operative engagement of the drive is maintained until the engine is reliably self -operat1ve.

It is an object of the present invention to provide a novel engine starter in which complete disengagement of the drive is dependent upon shifting the motorarmature to a decentered position with respect to the field.

It is another object to provide such a device in which means under the control ofthe operator are provided for shifting the armature into decentered position and positively holding it in such position in order to prevent undesired engagement of the gearing due to accelerational or gravitational forces of the vehicle on which the drive may be mounted.

It is another object to provide such a device in which the control of the decentering means for the motor armature is combined with the control of the starting motor switch.

Another object is to provide such a device incorporating means foryieldably holding the motor armature in centered position during the starting operation.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing, in which:

Fig. l is a side elevation partly in section of a portion of a starting motor and control mechanism therefor comprising a preferred embodiment of the invention, the remaining elements of the starting system being indicated diagrammatically;

Fig. 2 is a similar view of the Opposite end of the starting motor with the drive mounted thereon; and

Fig. 3 is a detail in perspective, partly broken away, of the overrunning clutch assembly.

This application has been divided, and the subject-matter of the novel starter gearing with normally. disengaged over-running clutch has been incorporated in the divisional application of Donald L. Miller, Serial Number 665,704 filed April 29, 1946.

In Fig. l of the drawing there is illustrated a starting motor I having an armature shaft 2 which is slidably journalled in the frame of the starting motor whereby it may be moved longitudinally so as to decenter the armature with respect to the motor field. Means for energizing the starting motor are shown comprising a battery 3 grounded at I and connected by a lead 5 to one terminal 6 of a starting switch indicated generally by numeral 1. A second terminal 8 of the starting switch is connected by a lead 9 to the starting motor, indicated diagrammatically at SM, which is grounded at H to complete the startin circuit. A bridging contact l2, mounted on a magnetic plunger I3, is arranged to connect the switch terminals 6 and 8 to close the starting switch when actuated by a solenoid l4, a spring l5 being provided to normally hold the switch open. Means under the control of the operator for energizing the solenoid H are provided comprising a lead l6 connected with the battery lead 5, a manual switch I! connected to the solenoid by a lead l8, and a ground connection l9.

A second plunger of magnetic material 2| is slidably mounted in the solenoid l4 and is provided at its lower end with a cam head 22 which enters the end bearing 23 of the starting motor in position to engage a thrust block 24 bearing on the end of the armature shaft 2. The plunger 2| is normally projected by a spring 25 into the position illustrated in Fig. 1 where the armature shaft has been cammed into its displaced or decentered position, and positively locked th'erein by engagement of the thrust block 24' with the side of the plunger head 22.

A casing 26 is provided for enclosing and supporting the magnetic starting switch and the shifting and locking means, the casing being at tached to the starting motor end bearing 23 in any suitable manner as indicated at 21.

The opposite end of the armature shaft 2 is provided with a smooth reduced extension 28 as illustrated in Fig. 2 on which is slidably journalled a pinion 29 that is adapted to mesh with and rotate a gear 3| of the engine to be started.

A driving sleeve 32 is fixed on the end of the armature shaft as by means of a pin 33, and has slidably journalled thereon a screw shaft 34 re tained thereon by a lock rin 35. The screw shaft is yieldably connected to the sleeve for 1ongitudinal and rotary movement by means of a drive spring 36 and anchor plates 31 and 38.

A driving clutch member 39 is threaded on the screw shaft and provided with teeth 4| arranged to engage corresponding teeth 42 on a driven clutch member 43 rigidly mounted as indicated at 44 on the pinion 29. Means for limiting the separation of the clutch members 39, 43 is provided comprising a sleeve 45 fixed to the driving clutch member as shown at 46, and having an intumed flange 41 adapted to engage the driven clutch member when the clutch members are separated sufiiciently to provide clearance between the teeth 4| and 42.

spring bears on the tapered portion and thereby The tends to separate the clutch members. spring 48 is also arranged to serve as a frictional torque transmitting member-between the two clutch members whereby a proper amount of control is established to secure reengagement of the clutch members after a false start and to transmit rotation from the pinion to the driving clutch-member 39 to secure demeshing f the pinion after the engine has started. The clutch member 39 may be normally retained in its idle positionas illustrated by any suitable form of anti-drift detent such as indicated at 50.

Means are preferably provided for y-ieldably holding the motor armature in centered position during cranking so as to prevent the pinion from floating away from its fully meshed position. As shown in Fig. 1, this may be accomplished by means of a spring-pressed detent 53 mounted in the motor :bearing 23 in position to enter a groove 54 in the armature shaft when the armature is in its centered position. When such a detent is us-ed,.it maybe found desirable to employ a short stiff spring 55 to assist the spring 25 in overcoming the effect of the detent and initiating the displacement of the shaft when the solenoid I4 is deenergized. Spring 55 is preferably made of such length as to be effective only when plunger 2| is near its retracted position, where the effect of the solenoidis sufficiently powerful to insure proper closure of the start-ing switch ll.

In operation, starting with the parts in the positions illustrated, closure of the manual switch I"! energizes the solenoid M which closes the starting switch 1 and also withdraws the plunger 2| against the action of spring 25. The energization of the starting motor causes the armature thereof to center itself, thus moving the armature shaft 2 to the left sufiiciently .to enter the ends of the teethof the pin-ion '29 into the tooth spaces of the engine gear 3|. At the same time, rotation of the armature shaft 2 is transmitted through the yielding connection 36, etc., to the screw shaft 34, whereby the driving clutch member 39 is threaded to the left, pushing the pinion along the armature shaft until it engages the shoulder 52 formed by the reduction in diameter thereof. When this occurs, the pinion is fully meshed with the engine gear and the further movement of the driving clutch member 39 causes the teeth 4| thereof to be forced into driving engagement with the teeth 42 of .the driven clutch member 43 whereupon a positive driving connection is established from the clutch member 39 to the pinion. The screw shaft 34 is thereby forced backwardly to the right, compressing and loading the drive spring '36 until sufficient torque has been built up to cause rotation of the engine gear to crank the engine.

When the engine fires, the acceleration of the pinion 29 is .transmitted through the clutch teeth 42, 4| to the threaded clutch member 39 which consequently thread-s itself back on the screw shaft 34 and disengages the clutch teeth. The pinion is kept inengagement with the engine gear 3| by reason of the centered position of the armature shaft 2, and overruns its driving connection freely and quietly since the spring 48 holds the clutch members disengaged.

Should the engine fail to continue self-operative, the consequent deceleration of the pinion 29 permits the tarting motor to catch up with it, whereupon, due to the frictional dragof the spring 48, the driving clutch member promptly threads itself to the left on the screw shaft, moving the pinion into full mesh and closing the clutch, whereupon cranking is resumed. When .the engine is reliably self-operative, the operator opens the manual switch thus deenergizing the solenoid and permitting spring l5 to open the starting switch and sprin 25 and to project the plunger 2| so as to overcome the effect of the detent 53 and cam the armature shaft 2 into its idle or displaced position.

Although but one embodiment of the invention has been shown and described in detail, it will be understood that other embodiments are possible and that variations in the design and arrangement of the parts may be made without departing from ,the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In a starting system for internal combustion engines a motor having a. longitudinally shiftable armature shaft, a plunger adapted to engage and move said shaft away from its normal running position, a pinion on the shaft having an overrunning clutch connection therewith, and movable with the shaft into and out of mesh with a gear of an engine to be started, and means under the control of the operator for withdrawing said plunger to thereby allow the armature of the motor to freely move to its normal running position.

2. In a starting system for internal combustion engines a motor having a longitudinally shiftable armature shaft, a pinion for the shaft having an overrunnlng' connection therewith and movable with .the shaft into and out of mesh with a gear of an engine to be started, means for moving the shaft longitudinally and holding it in a position where the pinion may be demeshed from the engine gear, a magnetically operated switch for the starting motor, and means whereby energiz'ation of the starting switch moves said holding means to inoperative position to thereby allow the armature of the motor to freely move to its normal running position.

3. In a starting system for internal combustion engines a motor having a longitudinally shiftable armature shaft, a spring-actuated plunger adapted to engage and move said shaft away from its normal running position, a pinion on the shaft having an overrunning clutch connection therewith and movable with the shaft into and out of mesh with a gear of an engine to be started, a switch for controlling the energization of the starting 'motor, electro-magnetic means for closing the switch, and means actuated by the electro-magnetic means for moving the plunger out of engagement with the shaft.

. 4. In an engine starter a motor having a longitudinally movable armature shaft, a pinion slidably journalled thereon for movement into and out of mesh with a gear of an engine to be started and having an overrunning driving connection therewith, means including a slidable plunger for moving the armature shaft in a direction to demesh the pinion, spring means for actuating the plunger, a solenoid'for retracting the plunger REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Conrad Nov. 13, 1917 Biiur July 1, 1919 Friedrichs Mar. 6, 1923 Royce Feb. 25, 1930 Louette Jan. 9, 1934 Whitney June 11, 1935 Martin Mar. 9, 1943 Jones Oct. 19, 1943 Kearney Jan. 18, 1944 Buxton Feb. 12, 1946 Buxton Mar. 19, .1946 Miller Mar. 19, 1946 

